Is it correct to call a picture book without any written content a book or is it only correct to call it an album?

Answer 1

This would still be considered a book for reference purposes. There is still a story there that the illustrator (author if you like) is trying to tell. Whereas, an album is considered a collection of different media or non connected media. For example, a family album has a collection of photos (connected to the theme of family), but does not tell a direct story. A music album is similar in that way. It is a collection of different songs, with different "stories". I hope this helps.